British Pat. No. 1,476,086, Bush Boake Allen, Ltd., June 1, 1977 relates to the removal of undesirable soy flavor components to obtain a bland product. The invention disclosed involves bubbling gas through a soy flour/water suspension to form a foam containing the undesirable flavor elements.
U.S. Pat. No. 3,142,571, McAnelly, July 28, 1964 discloses the preparation of soy materials by preparing a dough from soy flour, and cooking the dough using live steam. The resulting cooked dough is extracted by steeping it in or percolating it with water to remove water soluble flavor components.
Other methods for deflavoring soy materials use lower aliphatic alcohols in the extraction medium for removing the undesired flavor elements. U.S. Pat. No. 3,043,820, Beaber, et al., July 10, 1962 discloses a deflavoring process involving pretreating defatted soy flour with an alcohol, such as ethanol or methanol, and, subsequently, dissolving the pretreated protein in an aqueous solution, reprecipitating the protein through isoelectric precipitation and recovering the protein through centrifugation.
U.S. Pat. No. 3,630,753, Melnychyn, Dec. 28, 1971 discloses an alkaline extraction procedure in which the soy protein is solubilized at pH 9.5-12.5. The protein is subsequently isoelectrically precipitated, the mixture is centrifuged and the mixture is contacted with alcohol to improve the flavor.
U.S. Pat. No. 3,762,929, DeLapp, Oct. 2, 1973 discloses a deflavoring method for treating soybean flakes involving placing the flakes in aqueous contact with a polysaccharide such as carboxymethyl cellulose, carrageenan or agar and then separating the soy flakes.
U.S. Pat. No. 3,998,800, Youngquist, discloses a deflavoring process using a ternary single phase, flammable, solvent system comprising a mixture of water, a slightly polar oxygen-containing organic solvent, such as ethanol, and a nonpolar hydrocarbon, such as hexane.
U.S. Pat. No. 3,714,210, Schweiger, et al., Jan. 30, 1973 discloses the production of deflavored soy concentrate by using a two-phase ternary solvent system using solvents such as hexane, methanol, and water.
Two additional references relate to the separation of soy protein from residual cellular material. M. P. Tombs, Plant Physiology, 42, 797 (1967) describes a method of isolating protein bodies from soy meal by density gradient centrifugation using an aqueous sucrose solution, but does not disclose deflavoring effects. U.S. Pat. No. 3,794,735, Newsom, et al., Feb. 26, 1974 discloses the separation of protein from lipid-containing seeds using emulsification, centrifugation, isoelectric precipitation. Edible salts are added to decrease the viscosity of the final product.